Posted by Liz Ernst on Fri, Jun 24, 2011 @ 09:57 AM
For NASCAR drivers, crew members, staff and fans, the noise and reverberation that are Nascar's trademark may also be contributing to the most serious health issues fed by extended exposure to the painfully loud roar of four dozen revving engines, blasting around the half-mile oval racetrack at Bristol Motor Speedway. And these are just practice runs.
For many fans, the noise is is huge part of the excitement of Nascar. To the fans, who must shout to communicate, noise delivers the energy that keeps bringing them back for more.
The noise also makes it more hazardous not only for everyone else who spends time at a racetrack during a Nascar event. That is the finding from two studies by the National Institute for Occupational Safety and Health, or NIOSH, which reports that sound levels at tracks reach dangerously high decibel levels.
The first study by NIOSH, the government agency that conducts research on health and safety issues, was published by The Journal of Occupational and Environmental Hygiene in August 2005. It focused on tests conducted at Bristol Motor Speedway.
A co-author of the studies, Dr. Luann E. Van Campen, said NIOSH viewed Bristol as a worst-case scenario for noise because of the bowl-like stadium track surrounded by stands that rise 21 stories. Chemical and noise exposures were measured at Bristol and at an undisclosed race team shop. The study found chemical exposure to be low but noise exposure high.
“Employees involved in stock car racing are routinely exposed to extreme levels of noise, and auditory damage will ensue eventually,” according to the report’s conclusion. “More immediate concerns include the occupational risks posed by possible noise-induced fatigue, stress and miscommunication.”
Chucri A. Kardous, a NIOSH engineer and a co-author of the studies, said the noise level of 43 cars during a race was equivalent to a jet engine, which is 140 decibels.
“It’s higher than what we call here at NIOSH an allowable limit,” he said.
The second study, a follow-up that includes other tracks, was not available as it was being prepared for publication. But some of the results were presented last fall at a gathering of the Acoustical Society of America.
As in the first study, peak sound levels exceeded 140 decibels during races. To put that in perspective, noise becomes painful at 125 deciels; even short term exposure to decibel levels at 140 can cause permanent hearing damage. This is the loudest recommended exposure to noise with hearing protection. NIOSH typically recommends having protection when levels exceed 85. An abstract of the second study also noted how quickly the noise reached that level: “in less than a minute for one driver during practice, within 2 minutes for pit crew and infield staff, and 7 to 10 minutes for spectators during the race.”
That exposure could last for three or four hours, the duration of a race.
Kardous said he could not find any other studies of noise at racetracks. The Nascar spokesman Jim Hunter said officials had not focused on the matter since the 1970s, when noise became an issue primarily among people living near racetracks.
But the NIOSH findings are hardly a shock to those who spend time at the track. The seven-time champion Richard Petty has blamed racing for his hearing loss and now wears a hearing aid.
After 32 years of racing everything from go-karts to stock cars, including 14 seasons in Nascar’s premier Cup series, the driver Jeff Burton is a victim, too.
“My hearing’s not great, but there’s a reason for that,” he said as teams arrived for the Sharpie 500 race Saturday night. “When I was younger, I didn’t worry a whole lot about it. But I do now. Maybe too late.”
Many drivers use custom-molded plastic earplugs during races; Burton wears foam plugs. He said he did not know the Noise Reduction Rating for his ear protection. The rating indicates the number of decibels a protection device can block.
Crew members and other Nascar staff members typically wear communication headsets during races. Nascar requires its employees to wear protection. The headsets protect the ears but lose some of their effectiveness when the volume is turned up to allow communication among staff and crew. Fans who use similar headsets to listen in on scanners of driver-crew conversations face the same loss of protection, Kardous said.
There have been no studies conducted to determine the proper Noise Reduction Rating for drivers, crew members and fans at Nascar events. One of several recommendations from the first report included further studies on proper protection levels for earplugs and headsets. Those recommendations have not been followed.
Thais Morata of NIOSH, another co-author of the studies, said it would be up to Nascar, drivers or teams to approach the institute about further research. No studies are planned.
There may be another option. Nascar could use mufflers to reduce the noise during races.
“That’s the primary source of the noise, so obviously, that would be the top recommendation if we could make it,” Kardous said.
But Hunter said that Nascar tried mufflers in the 1960s and that they did not have a significant effect on decibel levels. Besides, it would be a hard sell for fans, who prefer to attend practices and races without any hearing protection.
Excerpted from an article by Viv Bernstein, published 2007, New York Times.